Method of treating yarn



y cotton is carded and spun into strands.

Patented Nov. 22, 1932 UNITEDv STATES PATENT oFFIcE JOSEPH 1. HOLT, 0F MERION, PENNSYLVANIA, ASSIGNOR T0 ABEBFOYLE MANUFACTUR- ING COMPANY, F CHESTER, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA METHOD OF- TBEATIN G YARN Application led March 23, 1931.

connection with the formation and treatmentf of cotton yarn, it'is understood that the invention is not limited thereby, but will apply to yarns other than cotton yarns.

In the manufacture of cotton yarn, 'Iaw he fibres of the strands are bound together b the spinning, so that they become twiste "t'ogether, each fibre aligning closely with its nei hbors.

' lhis single strand, as twisted in the spinning, is sometimes used as yarn in the formation of finely woven or knitted materials, while in other instances, a plurality of these strands are twisted together to produce a multiple strand yarn.

The raw cotton yarn, either in a single strand or composed of a plurality of strands, is usually bleached, mercerized and dyed, or

may be treated with a combinationof anyl of these steps in order to produce the iinished article.

In any or all of these treating yarn may be held under tension.

It has been found by experimentation that yarns are stiifened or made harder by any of these treatments and, conseqllliently, are less adaptable to the knitting mac ine than would be the case `if softer. Andl this hardness is not only present in the yarn'itself, but is carried on into the knitted goods so that they are harder or stiffer than goods manufactured with yarn treated in accordance with this invention.

Various 'processes have been advanced for the treatment of finished yarnl in order to Jps,`the

soften the same and render it more adaptable to the knitting machine and, consequently, to the roduction of. better knitted goods.

These processes, however, usually consist of treating the (yarn with conditioning oils or emulsions, an may be said to be chemical processes, as distinguished from mechanical processes.

Serial No. 524,608.

While all of these processes are helpful in varying degrees, none of them are capable of producing a softA yarn or a perfect yarn for the purpose specified. y

The object of this invention is to provide a process of mechanical treatment for softenmg yarn.

According to the invention, the yarn, after treatment, is untwisted to separate the fibres, and cause them to take up new relations with their neighbors.

It is a well-known fact that the processing of yarns, as by mercerization, putsfthem into a more or less plastic condition before dr ing. Then when they are dried, particular y if run over drying cylinders where the yarn 1s under some tension and is pressed'tightly against the cylinder surfaces, the fibres are.

in new positions. The result is that or example, have finer and` smoother appearance than the untreated yarn, d ue to a closer packing of the fibres.

Such yarns do not knit as well because the fibres cannot slip over one another as readily as before this packing or sticking together and,` therefore, do not accommodate themselves as readily tothe formation of loops in the knitting machine.

With mercerization, even aside from the drying influence, the tension on the yarn while it is wet tendsto make a hardermore compact structure. p

The ordinary methods of softenin employ materials like soaps, oils or fatty su stances. These materials may exert some softening effect on the individual fibres, but it seems more vlikely that they act through a lubricat- 111g effect. 'Thereis no evidence that they so ten yarn through any ,influence on the set of the fibres.

It is common experience that such softening usually does not add much to the knitting quality of yarns.

The basis of this invention is the attack of this problem ina more fundamental manner by breaking the set in the processed yarn. It is quite probable that durlng the process of untwisting or of untwisting and retwisting, every fibre in the yarn moves a little las ioc

with respect to its neighbors and, probably, never comes back to its original position.

The well-known twist relationsof two-ply yarns such as cotton of ordinary mercerizing twist, appears to establish this as a fact. It is established beyond all doubt that when a single strand yarn is m'ade at any twist, and then doubled into two-ply yarn by twisting in the opposite direction, an amount of twist comes out of the singles equal to that put into the two-ply; for example, if the single strand yarns are made at 15 twists per inch, and they are then doubled at 15`twists,the twist in the singles will practically all come out and the single yarns will contain almost no twist as they lie inthe two-ply.

This general behavior hasbeen verified in the laboratory of the Mellon Institute of Industrial Research, a department of the University of Pittsburgh, and is also covered in a very recent issue of Textile World (see Textile World of February 21, 1931, page 38) The reverse lis also true. The untwisting of a two-ply yarn puts twist back into the singles. This is readily demonstrated by the regular test for twist. The twist is first taken out of the two-ply, then-one strand is cut away, and vthe original twist is found in the remaining single strand yarns. Even though the single 'yarns .were practically without twist while in the two-ply, the full twist goes back into them on untwisting the two-ply.

v gle yarns from which it is made. This means that all of the fibres are moved more or less and change their positions, as shown by new twist angles.

' At this stage, the single strand yarns are temporarily tightened but the separate fibres are in new positions.

On retwisting the twist comes out of the single strand yarns and back into the twoply, but the tightening andloosening have been sufficient to break up the fibre set and soften the yarn. An observed increase in loose fibre ends confirms this general slight loosening of structure which has released them.

Although the effect produced in an ordiv nary yarn is scarcely visible, it is sufficient to make a very definite difference in knitting quality. Inknittings made with this specially treated yarn, it has been found that they show about 5% less width than with knittings made with the same yarn untreated by this process. This indicates a betten knitting quality, as commonly judged by the trade, and from the knitting point of View, is a-very real difference.

A very slight unpacking of the fibres or release of any sticking together would make the yarn more flexible and less stiff. While lthere is rather small visible difference in the knittings, their preference by the knitter and the general appearance and feel of the fabrics is highly persuasive.

There are two general methods by which this process may be carried out. Let us consider the first from the standpoint of untwisting and retwisting.. Let us considerv that a single strand of yarn is twisted about 15 times to the inch. This is its condition when mercerized and treated. This strand is then untwisted so as to leave about 4 or 5 twists to the inch and is then retwisted to add about 7 twists so as to bring it back to twists and the doubling twist will produce 7 a somewhat different effect.

Inthel accompanying drawing, I have endeavored to diagrammatically illustrate this phenomenon of the twists of multiple strand yarn by exaggerating the size thereof.

In the drawingy the fine lines show the directions of the single fibres or the twist angles.

In the original yarn, Figure 1, there is practically no twist angle as the fibres A tend to follow the axis of the single strand yarns. Let us assume that in this yarn of Figure 1 the doubling twist is about 14 twists to the inch and the single strand twist was 15.

In Figure 2I the doubling twist is reduced from 14 to 5 twists per inch andthe bres A show a distinct twist angle in the singles, because they have taken on4 twists with the untwisting of the two-ply.

In Figure 3 a part of the doubling twist has been put back and a corresponding amount of single twists have been taken out automatically by that same operation. The fibres in the yarn of Figure 3 are now at a smaller angle with the single strands of yarn than in ignre 2, and are intermediate between the conditions shown in Figures 1 and 2.

These views have been prepared from magnified yarn count 45/2 and they are not exaggerated.

Anyone can easily convince himself, by a few minutes experimenting with" a two-ply yarn of usual mercerizing twist, that the twist will run into or out of the singles with changes in the doubling. If a short length of the two-ply is held by its ends, andv one of the single strands removed, without disturbing the other, the one remaining will be found to b almost without twist and very weak. l

If, however, a piece of the two-ply is held at the end, as with knots, and untwisted with only the natural disturbance of the single strands, the single yarns will now be found to be twisted as well as stronger, and also inclined to kink, showing thatthe twist has gone into them.

This untwisting of the multiple ply yarn and the retwisting involves two operations on twisting machinery. A second or alternawtive method is proposed to eliminate one of these operations. I

When'the yarn is manufactured, it can havethe usual amount of twist in the singles,

but they can be .put together with a higher twist than usual.

' If `the yarn is mercerized or otherwise processed, the excess of twist in the doubling can be taken out, leaving the usual doubling twist. This step will, at the same time, bring the yarn down to the usual' singles twist.

Since the doubling and singles twist will have both been changed by this one untwisting operation,the yarn will have been sofuntwistin is only, done after the yarns have been har ened b other processes, hence its phenomenal r While the invention has been explained 1n connection with certain yarns and vcertain twists, it must be understood that these are for illustrative purposes only, and the description of these particular yarns and the steps in the -process may be modied and changed in various ways without de artin from the invention herein set fort an hereafter claimed.

The invention is hereby claimed as follows:

The herein described process of softening treated twisted yarns, comprising the steps of putting a number of twists in exce of the desired final twist into the yarn before treatment, and then partially untwisting the same after treatment. s

In testimony whereof I have signed my name to this specification.

JOSEPH P. HOLT.

tened in accordance with the explanation above and the final yarn will have theusual structure.

A slightly diferentmodification will yield y la still softer yarn.

The yarn is so designed that the untwisting will untwist both the lsingles and the two-ply at the same time, leavin the whole yarn structure slightly loosenefgl but at approximately the usual commercial twist or at an desired special twist. y

f To illustratethis last modification the single strand yarn could be made at 14 twists and then doubled in the two-ply with 18 twists. 'Ihis doubling would take all the twist out 4o` of the singles and put in d twists in the reverse direction to the original. If,.after processing, the yarn vis desired to have 14:

twists of doublingV twist, the 4 twists excess can be taken out and at the same time 4 re-S verse twists kin the singles will also come cut,

thus the. singles and the two-ply can both be slightly untwisted at the same time, a condition most favorable to maximum softening.

In this case, the result will be a balanced yarn with 14 twists in the doubling and 14 in the original singles.

ySince the untwistin is done after the processing, it is' obvious om the general twist relations already stated that these yarns will not be merely equivalent to softertwisted yarns. jThe special manipulation also undoes some of the harmful .electsof treats ing' yarn by tension, dryingand other operations, and this, yas already explained, is 60 the main point of the invention.

Itjmust be understood that' the special las twistprocesses which involve a permanent i taking out of twist lwill not produce results t equivalent to merely using yarns of less twist 5 'm the first place. .In this invention, the

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